2 Answers
2

Click on the button for "link" above the map. Paste that link into the browser and hit enter. Then, add &output=kml to the end of the URL, and hit enter. You will be prompted to download a KML file, which will contain all of the points in the map.

Seeing that there's no convinient way of doing this provided by Google, I've created a tiny online app for export of your starred locations to KML: http://gexport.somee.com/
It's very primitive, but it does the job.